In recent years, an active matrix type image display device using an organic EL device has been actively developed. The image display device using the organic EL device is an image display device using light emitting phenomenon of an organic thin film that emits light by being applied with an electric field. The organic EL device is able to be driven at an applied voltage of 10 [V] or less. Thus, in this kind of image display device, the electric power consumption is able to be decreased. Further, the organic EL device is a self-luminous device. Thus, this kind of image display device does not need a backlight unit, and accordingly weight saving and thickness saving are able to be realized. Further, the organic EL device has a characteristic that the response speed is high, about several u second. Accordingly, this kind of image display device has a characteristic that a residual image is hardly generated at the time of displaying videos.
Specifically, in the active matrix type image display device using the organic EL device, pixel circuits composed of the organic EL device and a drive circuit for driving the organic EL device are arranged in a state of matrix, and thereby a display section is formed. This kind of image display device displays a desired image by driving the respective pixel circuits by a signal line drive circuit and a scanning line drive circuit arranged around the display section respectively through a signal line and a scanning line provided in the display section.
For the image display device using the organic EL device, a method of configuring the pixel circuit by using two transistors is disclosed in Patent Document 1. According to the method, a configuration of the image display device is able to be simplified. Further, in the Patent Document 1, a structure to prevent threshold voltage variation and mobility variation of a drive transistor for driving the organic EL device and image quality deterioration with age of characteristics of the organic EL device is disclosed.